Metrics, techniques and recent developments In mixed-signal testing

This paper presents a tutorial on mixed-signal testing. Our focus is on testing the analog portion of the mixed-signal device, as the digital portion is handled in the usual way. We begin by first outlining the role of test in a manufacturing environment, and its impact on product cost and quality. We will look at the impact of manufacturing defects on the behavior of digital and analog circuits. Subsequently, we will argue that analog circuits require very different test methods than those presently used to test digital circuits. We will then describe four common analog test methods and their measurement setups. We will also describe how analog testing can be accomplished using digital sampling techniques. Finally, we shall close this tutorial with a brief description of several developments presently underway on the design of testable mixed-signal circuits. 1